Separable attachment-plug.



Patented June .1, 1909 H. HUBBELL. SBPARABLE ATTACHMENT PLUG.APPLIOATION FILED 001'. so. 1908.

\bw mm v lm ylimeoo eo z HARVEY HUBBELL, or ninnenron'r, CONNECTICUT.

.SEPARABIQE ATTACHMENT-PLUG.

' To all whom it may concern:

Be it known that I, HARvErHUBBEL-L, a-

T citizen of the United States, resid' at Bridgeport, county ofFairfield, State of onnecticut, have invented a new and useful 3 Searable Attachment Plu'g, of which the fol owing is a specification Thisinvention relates to separable attach" ment plugs for use in electriccircuits, and has forits general objects to simplify and cheapentheconstruction and to greatly re duce the size of the plug.

4 It isone of the objects of the invention to provide an attachment plucap which maybe made from any ordinary plastic composition as hardrubber, so called, but which shall be provided with aninsulatingheatresisting disk to which the electrical connections areattached thus giving to the structure all the In the accompanyingdrawing forming a making a advantages of hard rubber, so called, and

durable and perfectly safe structure. i

A further object of the invention is to providemea'ns for connecting thecable to the cap' in such a manner as to prevent theend of the cablefromv fraying and preventing the end of the cable from being partlypulled out from the cap and loose ends of the covering threads escaping.

A further object of the invention is to provide an attachment plug basein which the usual intermediate part of porcelain-within which thecontacts .enga e may be dispensed with and the base shal be soconstructed that the engagement of the contacts will take place. withinthe screw shell.

'With these andother objects in view-the invention consists incertain'cconstructions and in certain parts, improvements andcombinations which will be hereinafter described and 'then specificallypointed out in the claim hereunto appended part of this specification,Figure 1 is 2. iongitudinal section of my novel attachment plugcomplete;. Fig. 2 a detail sectional view illustrating in connectionwith Fig. 1 my novel mode of attaching the cable to the cap;

- Fig. 3 an inverted plan view of the base with the screw shell removed;Fi 4 a plan view of the base of the screw she l removed; and

. Fig. 5-is a section on the line 55 in Fig. 1,

looking in the direction of the arrows. p ,10 denotes the cap as awhole, 11 the base asa whole-and 12 the cable. The capcomprises upperand lower parts indicated re- Specification' of Letters Patent;Application filed October 30, 1908. Seriai No. 460,239. I

ratmeaiune 1, 1909.

tlvely with male and female threads by which they are secured together.Both of these aarts may be molded from hard rubber, so'ca e I spectivelyby 13 and 14; and provided respec- I "115 denotes an internal recess inthe .cap

intowhich the cable leads through a central hole 16in part 13.

L7 denotes the contact plates which are secured in the recess and extendthrough -material that will resist heat.

slots-1S in the bottom part 1 1 of the cap.

- An important feature of the present inven- :tion is-that theelectrical'conneotions are attached to an insulatingheat-resisti washerindicated by 19. This washer may e made of mica, vulcanized fiber orany. insulating This insulating washer lies at the bottom of recess 15.Thebases of the contact plates, indicated by 20, are riveted orotherwise secured to the upper side of the washer and the platesthemselves extend. throu h slots in the washer in alinement with s ots18-inpart 14.

2 1 denotes the binding screws which en gage tliebases of the contactplates, and 22 the current wires which engage the.binding screws in theusual manner.

jAnotl1er important feature of the inven- I tion is the mode ofconne'ctingthe cable to 1 the cap. 23 denotes a beveled recess in theunder side of art 13 and surrounding the holefor the ca 1e and 24denotes a soft rubber rin which ,lies in this recess and clamps the-endof the cable firmly when part 13 of the cap is screwed to place (seeFigs. 2

' and 1). In assembling, the cable is passed through part 13 of the capand the ring, as clearly shown in Fig. 2, the loose threads at:

the end ofthelc able being below the ring.

When the parts are secured together by".

means of the screw threads, this soft rubber ring will becompressed'between the binding screws, the bases of the contact plates,part 13 and the cable into a more or less triangular form in crosssection, as shown in Fig. 1,

and will grip the cable tightly, wholly preventing the-loose threads at.the end of the cable from being pulled through the cap; inother words,

reventing the cable from be coming frayed above the cap.

Another and vitally important feature of the present invention is thatthe usual intermediate part of porcelain, lying wholly abovefthe screwshell, within which the engagernent of the contact plates with thecontact springsgis made, is dispensed with and has heretofore beenpossible.

the engagementof the contact plates and contact springs is caused totake place with in 'thescrew shell. I thereby materially reduce the costof construction and am enabled to make the attachment plug as a Wholeapproximately a third shorter than The base comprises an insulatingblock, preferably of porcelain, indicated'by 25, a cupped screwshellindicated by 26, and an insulating disk 27 ordinarily made ofvulcanized fiber to which the screw shell is secured. -The upper end ofthe screw shell-is shown as reduced slightlyin diameter, as at 28, andsaid reduced portion is inclosed in an insulating ringf29 which restsupon the upper end of the threaded portion of the shell. The purpose ofthis ring is to prevent the hand from coming in contact with'thelive endof the-shell in making.

and breaking the connection. The insulating block is provided near itslower end with a shoulder 30 which supports a cylindricalinsulating'lining indicated by 31 and over the outer edge of which thelower end of the screw shell is turned.

32 and 33 denote recesses in the insulating V block which receive thecontact springs indicated by 34 and 35. Contact spring 34 is.

secured to the screw shell by a rivet 36 which also secures the screwshell'to insulating disk 27. The screw shell is secured to theinsulating disk by additional rivets, one of which appears in dottedlines in Fig. 1. Contact s ring is secured -to the insulating block ymeans of a screw 37 which extends upward through the block and engages anut 38. The screw shell and the insulating disk are provided withcorresponding slots 39.

through which the contact p ates pass to engage the contact springswhen. the cap and base are connected. The passage ofthe current,starting from the left binding screw, is

as follows: through the left contact plate for the passage of contactplates and contact springs within the body and attached to the body andscrew shell respectively, which are adapted to engage the contactplates.

In testimony whereof I affix my signature, in presence of two witnesses.

\ HARVEY H BELL. Witnesses: I

A. M. WOOSTER, S. W. A'rrrERroNt

